/Engine/Source/Runtime/Engine/Classes/Materials/MaterialLayersFunctions.h
void InsertLayerCopy ( const [FMaterialLayersFunctionsRuntimeData](API\Runtime\Engine\Materials\FMaterialLayersFunctionsRuntimeD-) & Source, const [FMaterialLayersFunctionsEditorOnlyData](API\Runtime\Engine\Materials\FMaterialLayersFunctionsEditorOn-) & SourceEditorOnly, int32 SourceLayerIndex, EMaterialLayerLinkState LinkState, int32 LayerIndex )